William Williams Pantycelyn (1717-1791) was a prominent Welsh hymn writer and a key figure in the development of Welsh religious music. He is best known for his contributions to the genre of hymnody, particularly within the context of the Methodist revival in Wales. His hymns are characterized by their emotional depth and theological clarity, reflecting the revivalist spirit of the 18th century. Notable works include "O Fryniau Caersalem" (On the Hills of Zion) and "Duw, sy’n greador byd" (God, Creator of the World), which are still sung in churches today. Pantycelyn's hymns are often set to traditional Welsh tunes, making them accessible and popular among congregations. His impact on music is significant; he is regarded as the father of Welsh hymnody and played a crucial role in shaping the Welsh language's musical culture. Pantycelyn's work not only influenced church music but also contributed to the broader cultural revival in Wales, promoting a sense of national identity through song. His legacy endures, as his hymns continue to be integral to Welsh worship and culture.